Pouch container packaging and pouch container

ABSTRACT

A pouch container and a pouch container packaging prevents oblique seals from turning back, thereby reducing risk of leakage from the pouch container. The pouch container packaging includes a pair of outer films disposed on front and back sides with a spout sandwiched at the top. Each outer film has side edges, a bottom and oblique edges lying between the side edges and the bottom edge. Pair of gusset films is disposed in a folded state between outer films and each has side and oblique edges. Side seals are provided by joining side edges of the outer films to the side edges of the gusset films. A bottom seal is provided by joining outer films along their bottom edges. Oblique seals are provided by joining oblique edges of outer films to oblique edges of gusset films. At least a portion of an inner edge of each oblique seal is curved.

TECHNICAL FIELD

The present invention relates to a pouch container packaging and also toa pouch container.

BACKGROUND ART

Pouch containers are commonly used as containers for beverages such assports drinks and for foods such as ice cream and jelly. Patent Document1 discloses an example of a conventional pouch container. FIG. 13 showsa packaging for producing a pouch container disclosed in PatentDocument 1. The packaging X shown in the figure includes a pair of outerfilms 91, a pair of gusset films 92, and a spout 93. The pair of outerfilms 91 are disposed on the front and the back. The pair of gussetfilms 92 are each located in a folded state between the pair of outerfilms 91.

To be able to hermetically hold substances, such as beverages and foodsmentioned above, the packaging X has a top-edge central seal 94,top-edge side seals 95, side seals 96, a bottom seal 97, and obliqueseals 98. The top-edge central seal 94 is formed by joining the pair ofouter films 91 along the top edges with the spout 93 sandwiched betweenprotons of the top edges . The top-edge side seals 95 are formed byjoining the pair of outer films 91 to the pair of gusset films 92 alongthe top edges. The side seals 96 are formed by joining the pair of outerfilms 91 to the pair of gusset films 92 along the side edges. The bottomseal 97 is formed by joining the pair of outer films 91 along therespective bottom edges. The oblique seals 98 are formed by joining thepair of outer films 91 to the pair of gusset films 92 along the obliqueedges. The packaging X is such that an inner edge 96 a of each side seal96, an inner edge 97 a of the bottom seal 97, and an inner edge 98 a ofeach oblique seal 98 are substantially parallel to their outer edges andare straight throughout their length.

A method for producing a pouch container using a packaging X may includea leak testing step to check for leakage prior to a step of filling withan above-mentioned substance. In the leak testing step, a nozzle Nzshown in FIG. 13 is inserted into the spout 3, for example. Next, asshown in FIG. 14, air for example is blown in through the nozzle Nzinstantaneously within a short period of time (two seconds or so). FIG.14 shows the state where the packaging X starts to inflate with the airblown in. With completion of the air blowing, the packaging X is fullyinflated as shown in FIG. 15 . The packaging X in this state is checkedfor air leakage. Only if no leakage is detected, the packaging X isfilled with the substance.

Unfortunately, the leak testing step may cause an oblique seal 98 to beturned back as shown in FIG. 15 . For the convenience of clarity in thefigure, portions of the oblique seals 98 are shaded to indicate part ofthe outer films 91, whereas portions of the oblique seal 98 are leftunshaded to indicate part of the gusset films 92. Among the four obliqueseals 98 shown in the figure, the oblique seal 98 at the lower left isturned back so that the portion being part of the gusset film 92 isexposed on the bottom. As a result that the oblique seal 98 is turnedback, the bottom seal 97 is raised.

After completion of the leak testing step, the interior space of thepackaging X is evacuated and thus the packaging X becomes flat again.Subsequently, the step of filling the packaging with the substance isperformed. An edge once turned back in the leak testing step has acrease that remains even after the packaging is flat again. As such, itoften happens that the edge is unintentionally turned back again duringthe filling step. A pouch container having such a turned back edgeinvolves a risk of unintentional stress applied to the bottom during,for example, a transportation step, and a consequent risk of leakage.This may undesirably result in leakage of the substance from a pouchcontainer X despite that the pouch container is produced by using thepackaging X determined to be leakage free in the leak testing step.

REFERENCE LIST Patent Document

Patent Document 1: JP-A-2000-344252

SUMMARY Problem to be Solved by Invention

The present invention has been conceived in view of the abovecircumstances and aims to provide a packaging for a pouch container aswell as a pouch container capable of effectively preventing an obliqueedge from turning back and reducing the risk of leakage of the substancefrom the pouch container.

Solution to Problem

According to a first aspect of the present invention, there is provideda packaging for a pouch container, which includes: a pair of outer filmsdisposed on a front side and a back side with a filling-and-pouringmember sandwiched at a top, where the outer films each have side edges,a bottom edge and oblique edges lying between the side edges and thebottom edge; and

a pair of gusset films each disposed in a folded state between the outerfilms and having side edges and oblique edges. The side edges of theouter films and the side edges of the gusset films are joined to provideside seals, the bottom edges of the respective outer films are joined toprovide a bottom seal, and the oblique edges of the outer films and theoblique edges of the gusset films are joined to provide oblique seals.The oblique seals each have an inner edge at least a part of which iscurved.

According to a preferred embodiment of the present invention, eachoblique seal has a narrow-width portion that is narrower in width thanends of the oblique seal.

According to a preferred embodiment of the present invention, the inneredge of each oblique seal has a curved portion continuous with an inneredge of a side seal.

According to a preferred embodiment of the present invention, the inneredge of each oblique seal has a curved portion continuous with an inneredge of the bottom seal.

According to a preferred embodiment of the present invention, theentirety of the inner edge of each oblique seal is curved.

According to a second aspect of the present invention, there is provideda pouch container that includes a packaging according to the firstaspect of the invention; and a substance contained in the packaging.

Advantages of Invention

According to the present invention, at least a portion of the inner edgeof each oblique seal is curved. With this arrangement, the stress on theoblique seal along the entire length of the inner edge is not uniform inthe longitudinal direction but varies gradually in accordance with theshape of the curve. This serves to prevent the stress on the inner edgeof the oblique seal from being rapidly concentrated at the end connectedto an end of the side seal and at the end connected to an end of thebottom seal, ensuring the stress to be distributed. Consequently, theoblique seals are prevented from turning back and the bottom seal isprevented from rising. Therefore, a pouch container produced by usingthe packaging can significantly reduce the risk of leakage of thesubstance as compared with a conventional pouch container.

Other features and advantages of the present invention will become moreapparent from detailed description given below with reference to theaccompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a front view of a packaging according to a first embodiment ofthe present invention.

FIG. 2 is a sectional view taken along line II-II of FIG. 1.

FIG. 3 is a sectional view taken along line of FIG. 1.

FIG. 4 is a perspective view illustrating a leak testing step in amethod for producing a pouch container from the packaging of FIG. 1.

FIG. 5 is a perspective view illustrating the leak testing step in themethod for producing the pouch container from the packaging of FIG. 1.

FIG. 6 is a perspective view of an example of a pouch containerincluding the packaging of FIG. 1.

FIG. 7 is a sectional view taken along line VII-VII of FIG. 6.

FIG. 8 is a partial front view of a packaging according to a secondembodiment of the present invention.

FIG. 9 is a partial front view of a packaging according to a thirdembodiment of the present invention.

FIG. 10 is a partial front view of a packaging according to a forthembodiment of the present invention.

FIG. 11 is a partial front view of a packaging according to a fifthembodiment of the present invention.

FIG. 12(a)-(d) is partial front views of packagings of comparativeexamples.

FIG. 13 is a perspective view illustrating an example of a method forproducing a pouch container using a conventional packaging.

FIG. 14 is a perspective view illustrating an example of the method forproducing the pouch container using the conventional packaging.

FIG. 15 is a perspective view illustrating an example of the method forproducing the pouch container using the conventional packaging.

MODE FOR CARRYING OUT INVENTION

Preferred embodiments of the present invention are described below withreference to the accompanying drawings. In the description, the front ofa pouch container is toward a customer when the pouch container holdingthe contents is placed to stand upright on a store shelve. Further, theback of the pouch container is opposite to the front, the sides are inthe right and left directions, the top is in a vertically upwarddirection, and the bottom is in a vertically downward direction. Anouter surface of each film of a pouch container refers to a surfaceexposed to the outside, and an inner surface refers to the oppositesurface. In addition, an up-and-down direction refers to the verticaldirection of the pouch container standing upright, and a width directionrefers to the right-and-left direction.

FIGS. 1 to 3 show a packaging for a pouch container according to a firstembodiment of the present invention. The packaging A1 of the presentembodiment is formed from a pair of outer films 1, a pair of gussetfilms 2, and a spout 3 so as to have a top-edge central seal 41, fourtop-edge side seals 42, four side seals 43, a bottom seal 44, and fouroblique seals 45. FIG. 1 is a front view of the packaging A1, FIG. 2 isa sectional view taken along line II-II of FIG. 1, and FIG. 3 is asectional view taken along line of FIG. 1.

The pair of outer films 1 are disposed on the front and the back tosandwich the spout 3 at the top. Each outer film 1 according to thepresent embodiment is generally hexagonal as seen from the front and hasa top edge that extends in the width direction at the top, two sideedges that are spaced apart in the width direction and extend in theup-and-down direction, a bottom edge that extends in the width directionat the bottom, and two oblique edges each connecting the lower end of aside edge to the upper end of a bottom edge.

The pair of gusset films 2 are each located between the pair of outerfilms 1 in a state folded along a fold line 21. Each gusset film 2 has atop edge, two side edges, and two oblique edges and is generallypentagonal when unfolded. In addition, the gusset film 2 has cutawayportions 22 at either end of the top edge.

The pair of outer films 1 and the pair of gusset films 2 are typicallyformed from resin films. The resin films are required to have propertiesexpected for a packaging material, including impact resistance, abrasionresistance, and heat resistance. Typically, the seals described aboveare formed by heat sealing, and thus the sheets are required to haveheat sealing properties suitable for that. Appropriate sheets include amultilayer sheet of a base-film layer and a sealant layer that impartsthe heat sealing properties . Ina case where high gas impermeability andlight-shielding characteristics are required, an appropriate multilayersheet may be provided with a barrier layer between the base-film layerand the sealant layer. Alternatively, the base-film layer per se may beimparted with barrier characteristics. In this case, the barrier layeracts as the base-film layer, and thus the multilayer sheet includes thebarrier layer and the sealant layer.

The following lists examples of component materials of the base-filmlayer, sealant layer, and gas barrier layer.

These layers can be stacked through a conventional lamination technique,examples of which include co-extrusion lamination, dry lamination withadhesive, thermal lamination of thermally bonding layers via aheat-sensitive adhesive layer sandwiched in between.

Examples of the base-film layer include single-and multi-layer films,either oriented or non-oriented, made from polyester (such as,polyethylene terephthalate (PET), polyethylene naphthalate (PEN),polybutylene terephthalate (PBT), and polycarbonate (PC)), polyolefin(such as polyethylene (PE) and polypropylene (PP)), polyamide (such asNylon-6 and Nylon-66) , polyacrylonitrile (PAN) , polyimide (PI),polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), polymethylmethacrylate (PMMA), and polyethersulfone (PES).

Examples of the sealant layer include single-and multi-layer films,either oriented or non-oriented, made from low-density polyethylene(LDPE), linear low-density polyethylene (LLDPE), ethylene-propylenecopolymer (EP), cast polypropylene (CPP), bi-axially oriented nylon(ON), ethylene-olefin copolymer, ethylene acrylic acid (EAA) copolymer,ethylene-methyl methacrylate (EMMA) copolymer, and ethylene-vinylacetate (EVA) copolymer.

Examples of the gas barrier layer include: a thin film of metal such asaluminum; or a film of resin such as polyvinylidene chloride (PVDC),ethylene vinyl alcohol (EVOH) copolymer and any synthetic resin (whichmay be the base-film layer), each film of resin having a deposited (orsputtered) layer of aluminum or inorganic oxide such as aluminum oxideor silica.

The outer films 1 or the gusset films 2 may be provided with a printlayer (not shown) for printing of information related to the substance,including the product name, row materials, and product description, suchas precautions for use, in addition to various patterns and designs. Inone example, the print layer may be provided on the inner surface of thebase-film layer by a known method such as gravure printing.

The top-edge central seal 41 is formed by heat sealing to join the pairof outer films 1 centrally along the top edges. The top-edge centralseal 41 is located between the pair of gusset films 2. In the presentembodiment, the spout 3 is sandwiched at the center of the top-edgecentral seal 41. The top edges of the pair of outer films 1 and thespout 3 are hermetically joined by, for example, heat sealing.

Each top-edge side seal 42 is formed by heat sealing to join a side endof the top edge of an outer film 1 to a side end of the top edge of agusset film 2 . In the present embodiment, the pair of outer films 1 andthe pair of gusset films 2 form four top-edge side seals 42 in total.

Each side seal 43 is formed by heat sealing to join a side edge of anouter film 1 to a side edge of a gusset film 2 and extends in theup-and-down direction. In the present embodiment, the pair of outerfilms 1 and the pair of gusset films 2 form four side seals 43 in total.

The bottom seal 44 is formed by heat sealing to join the pair of outerfilms 1 along the respective bottom edges and extends in the widthdirection. The bottom seal 44 is located between the pair of gusset film2.

Each oblique seal 45 is formed by heat sealing to join an oblique edgeof an outer film 1 to an oblique edge of a gusset film 2. The obliqueseal 45 extends obliquely relative to both the up-and-down direction andthe width direction. In the present embodiment, the pair of outer films1 and the pair of gusset films 2 form four oblique seals 45 in total.The two oblique seals 45 located on the same side in terms of the widthdirection are continuous with the same widthwise end of the bottom seal44.

Each side seal 43 has an inner edge 43 a, the bottom seal 44 has aninner edge 44 a, and each oblique seals 45 has an inner edge 45 a. Inthe present embodiment, the inner edge 43 a is a straight line in theup-and-down direction throughout its length. The inner edge 44 a is astraight line in the width direction throughout its length. The inneredge 45 a is curved outward throughout its length. In other words, theinner edge 45 a is curved at any portions, including a portioncontinuous with the inner edge 43 a of the side seal 43, a portioncontinuous with the inner edge 44 a of the bottom seal 44, and anintermediate portion located in between. In FIG. 1, cross-hatchedportions along the inner edges 45 a indicate curved portions of theinner edges 45 a. In this embodiment, the entire length of each inneredges 45 a is cross hatched.

Each oblique seal 45 is structured to have a smaller width W3 around themiddle than widths W1 and W2 at the ends. This is because the inner edge45 a is defined by an outward curve at least partly, and indeed entirelyin the present embodiment.

In the present embodiment, the packaging A1 has two sealed shoulders 46.The sealed shoulders 46, which are located at the intersections of thetop edge with the side edges, are formed by heat sealing to join theinner surfaces of the pair of outer films 1 at portions exposed throughthe cutaway portions 22 in the gusset film 2.

The spout 3 is a hollow member made of, for example, resin and defines apath through which the substance is poured in and out . The spout 3 hasa tubular portion through which the substance is poured in and out and aboat-shaped welding portion joined to the sheet packaging body. Thespout 3 is secured to the pair of outer films 1 with the boat-shapedwelding portion hermetically sealed between the pair of outer films 1 atthe top-edge central seal 41. The spout 3 corresponds to afilling-and-pouring member according to the present invention.

FIGS. 4 and 5 show a leak testing step in a method for producing a pouchcontainer using a packaging A1. Prior to this, the packaging A1 isproduced through a commonly known production method, which typicallyinvolves appropriately folding and overlaying a plurality of materialsheets, and then heat sealing appropriate portions. Then, the materialsheets are cut out to obtain the packaging body. Then, the boat-shapedwelding portion of the spout 3 is placed between the outer films 1 at atop of the packaging body and hermetically sealed together by heatsealing. In this manner, the packagings A1 are produced one by one. Theleak testing step is performed mainly to check the heat sealed portionsfor any unintentional leakage.

First, as shown in FIG. 4, a nozzle Nz may be inserted into the spout 3of the packaging A1. The nozzle Nz is used in the leak testing step toblow air in. As the blowing of air through the nozzle Nz starts, thepressure in the space enclosed by the pair of outer films 1 and the pairof gusset films 2 rises, causing the packaging A1 to inflate.Eventually, the packaging A1 is fully inflated as shown in FIG. 5. Theblowing of air is carried out instantaneously, or within a short periodof time (two seconds or so) . At this stage, none of the four obliqueseals 45 are turned back, and the bottom seal 44 is in an appropriatestate of lying flat along one of the outer films 1. Once the packagingA1 is fully inflated, the packaging A1 is kept in the inflated state andtested for any air leakage using, for example, a sensor not shown in thefigures . The test takes about two to three seconds . If leakage isdetected, the packaging A1 is rejected for use in the subsequent stepsas being incapable of holding the substance. Upon completion of the leaktesting step, the interior space of the packaging A1 is evacuated withina short period of time (one second or so). As a result, the packaging A1becomes flat again.

The packaging A1, which is in a flat state, is subjected to the fillingstep using a conventionally known technique. Through this, the packagingA1 filled with the substance Lq is obtained as a pouch container B1shown in FIGS. 6 and 7. After the substance Lq is filled, a cap 31 isattached in threaded engagement with the spout 3.

Next, effects of the packaging A1 are described.

The conventional packaging X often experiences a turned back edge in theleak testing step. Although the cause is not fully identified, thefollowing is a possible explanation. In the leak testing step of theconventional packaging X shown in FIGS. 13 to 15, an increase in theinternal pressure of the packaging X creates stress on the inner edges96 a of the side seals 96, the inner edge 97 a of the bottom seal 97,and the inner edges 98 a of the oblique seals 98 in accordance with therespective shapes. Each of the inner edges 96 a, 97 a, and 98 a is astraight line and thus subjected to a stress resulting from the forcetending to push the edge outward with the edge kept straight. In otherwords, the stress on the inner edges 96 a, 97 a, and 98 a tends to berelatively uniform in the magnitude and direction substantially alongthe entire length except for the end portions. On the other hand, sincethe force is uniform substantially along the entire length, the stresstends to concentrate locally at the points of connection between theinner edges 96 a and 98 a and between the inner edges 97 a and 98 a. Inaddition, since air is intensively blown in within a short period oftime, the relevant portions of the packaging are abruptly pushedoutward. The present inventors assume that these circumstances create aforce tending to locally bend the connected portions of the side seal 96and the oblique seal 98 and of the bottom seal 97 and the oblique seal98. This may consequently result in that an oblique seal 98 is turnedback and the bottom seal 97 is raised as shown in FIGS. 14 and 15.

Based on the above findings, each oblique seal 45 according to thepresent embodiment has a curved inner edge 45 a as shown in FIG. 1.Thus, the stress on the inner edge 45 a is not uniform in thelongitudinal direction but varies gradually in accordance with the shapeof the curve . This serves to prevent the stress on the inner edge 45 afrom being concentrated at the ends where the oblique seal 45 isconnected to the side seal 43 and where the oblique seal 45 is connectedto the bottom seal 44, so that the stress is distributed. Consequently,the oblique seals 45 are prevented from turning back and the bottom seal44 is prevented from rising. Naturally, a risk of leakage of thesubstance is reduced for a pouch container produced by using thepackaging A1.

Each oblique seal 45 has a portion having the width W3, which is smallerthan the width W1 or W2 at the end portions. That is, the inner edge 45a of the oblique seal 45 defines an outward curve. Through the study ofthe present inventors, it has been found that such an outwardly curvedcontour is effective to prevent occurrences of turned back edges.

The method for producing a pouch container may be modified to fill thepackaging with the substance without performing the leak testing step.However, the filling step still involves the risk that the oblique seals45 are turned back and the bottom seal 44 is raised. Therefore, in sucha method, providing the oblique seals 45 with the inner edges 45 a thatare at least partly curved is likewise effective to prevent the obliqueseals 45 from turning back and the bottom seal 44 from raising.

FIGS. 8 to 11 show other embodiments of the present invention. Thefigures use the same reference signs for the same or similar elementsdescribed in the above embodiment. Similarly to FIG. 1, these figuresshow cross-hatched portions to indicate the curved portions of the inneredges 45 a.

FIG. 8 shows a packaging for a pouch container according to a secondembodiment of the present invention. The packaging A2 according to thepresent embodiment is such that each oblique seal 45 has an inner edge45 a that is entirely curved. In addition, each side seal 43 has aninner edge 43 a that is curved at a portion toward the inner edge 45 a,and the bottom seal 44 has an inner edge 44 a that is curved at portionstoward the inner edges 45 a. As shown in the figure, the inner edge 43 ais seamlessly continuous with the inner edge 45 a. In other words, theinner edge 43 a and the inner edge 45 a together define a curve at aconnected portion. In addition, the inner edge 44 a is seamlesslycontinuous with each inner edge 45 a. In other words, the inner edge 44a and the inner edge 45 a together define a curve at the connectedportion. With respect to the packaging A2 according to the presentembodiment, each oblique seal 45 has a portion with the width W3, whichis smaller than the widths W1 and W2 at the ends . This embodiment iseffective to prevent the stress on each inner edge 45 a from beingconcentrated at the ends. In addition, the present embodiment is moreeffective in preventing the stress on each inner edge 43 a from beingconcentrated at the end toward the inner edge 45 a and the stress on theinner edge 44 a from being concentrated at the ends toward therespective inner edges 45 a. Therefore, the present embodiment isappropriate to prevent the oblique seals 45 from turning back and thebottom seal 44 from raising.

FIG. 9 shows a packaging for a pouch container according to a thirdembodiment of the present invention. The packaging A3 according to thepresent embodiment is such that each oblique seal 45 has an inner edge45 a that is curved only at an end closer to the inner edge 43 a andstraight at the other portion. In addition, the inner edge 43 a iscurved at a portion toward the inner edge 45 a such that the inner edge43 a is seamlessly continuous with the inner edge 45 a. In other words,the inner edge 43 a and the inner edge 45 a together define a curve atthe connected portion. According to the present embodiment, each inneredge 45 a is curved only partly but still effective to prevent stressconcentration at the ends as compared with the inner edge 45 a beingentirely straight. The present embodiment is expected to be particularlyeffective to prevent the stress on the inner edge 45 a from beingexcessively concentrated at the ends toward the inner edge 43 a. Thiscan prevent a force tending to locally bend the connection portionsbetween the side seals 43 and the oblique seals 45. Therefore, theoblique seals 45 are prevented from being turned back.

FIG. 10 shows a packaging for a pouch container according to a fourthembodiment of the present invention. The packaging A4 according to thepresent embodiment is such that each oblique seal 45 has an inner edge45 a that is curved only at an end closer to the inner edge 44 a of thebottom seal 44 and straight at the other portion. In addition, the inneredge 44 a is curved entirely, and the inner edge 44 a is seamlesslycontinuous with the inner edges 45 a. In other words, the inner edge 44a and the inner edge 45 a together define a curve at the connectedportion. As stated with reference to the packaging A3, the partly curvedinner edges 45 a is effective to prevent stress concentration at the endthereof. The present embodiment is particularly expected to be effectiveto prevent the stress on the inner edge 45 a from being concentrated atthe end toward the inner edge 44 a.

FIG. 11 shows a packaging for a pouch container according to a fifthembodiment of the present invention. The packaging A5 according to thepresent embodiment is such that each inner edge 45 a is curved to definean outward bulge at a central portion. With such a configuration, theoblique seal 45 has the width W3 around the middle that is significantlynarrower than the widths W1 and W2 at the ends. The present embodimentprovided with the inner edges 45 a that are partly curved in this mannerare likewise effective to prevent stress concentration at the endsthereof and thus expected to be effective to prevent the oblique seals45 from turning back and the oblique seals 45 from raising.

Table 1 blow shows the results of tests conducted on the packagings A1to A5 according to the present invention, the conventional packaging Xshown in FIG. 13, and packagings C1 to C5 according to comparativeexamples shown in FIG. 12. In the tests, occurrences of turned backedges at the oblique seals 45 were checked.

TABLE 1 Packaging A1 A2 A3 A4 A5 X C1 C2 C3 C4 Occurrence 21% 23% 25%38% 31% 51% 73% 66% 58% 51% of turned back edges

The packagings A1 to A5 are structured as described above. The packagingX is structured as shown in FIG. 13 to have the inner edge 45 a of eachoblique seal 45 composed only of a single straight line. FIG. 12 showsthe packagings C1 to C4 according to the comparative examples. Asdescribed below, the packagings C1 to C2 are different mainly in shapeof the oblique seals 45 and common in that the inner edges 45 a arecomposed of straight lines.

In the packaging C1 shown in FIG. 12(a), the inner edge 43 a of the sideseal 43 meets the inner edge 45 a of the oblique seal 45 at a largerangle than in the packaging X. More specifically, the intersectionbetween the inner edge 43 a and the inner edge 45 a is shifted upward.In addition, the inner edge 45 a has a bend point. In the packaging C2shown in FIG. 12(b), the inner edge 44 a of the bottom seal 44 meets theinner edge 45 a of the oblique seal 45 at a larger angle than in thepackaging X. More specifically, the angle mentioned above is larger as aresult that the width of the bottom seal 44 is larger.

In the packaging C3 shown in FIG. 12(c), the inner edge 45 a has a bendpoint around the middle thereof, and the width of this middle portion issignificantly smaller than the width at either end. The packaging C4shown in FIG. 12(d) has the oblique seal 45 that is narrower throughoutits length than in the packaging X.

The test results about the occurrences of turned back edges shown inTable 1 were obtained on 50 samples of the individual packagings, namelythe packagings A1 to A5, X, and C1 to C4. Each sample was subjected tothe leak testing step to visually check the oblique seals 45 for anyturned back edge.

As shown in Table 1, the conventional packaging X exhibited theoccurrence rate of 51%, whereas the packagings A1 to A5 according to thepresent invention all exhibited the occurrence rates ranging from 21% to38%, which are lower than the rate obtained on the packaging X. That is,the occurrences of turned back edges were reduced by providing theoblique seal 45 having an inner edge 45 a at least partly curved. Inparticular, the packagings A1, A2, and A3 respectively exhibited theoccurrence rates of 21%, 23%, and 25%, each of which is about a half ofthe occurrence rate of the packaging X . That is , the occurrences ofturned back edges were sufficiently reduced. This is assumed to be aresult achieved by the inner edges 45 a being entirely curved. In thepackagings A3 and A4, each inner edge 45 a is curved only at a portiontoward the bottom seal 44. As demonstrated by the occurrence rate of38%, these packagings still achieved the effect of reducing theoccurrences of turned back edges. Comparison between the packaging A3and the packaging A4 reveals that the occurrences of turned back edgeswere reduced more effectively by providing a curve at the connectionbetween the inner edge 43 a of the side seal 43 and the inner edge 45 aof the oblique seal 45 than at the connection between the inner edge 44a of the bottom seal 44 and the inner edge 45 a of the oblique seal 45.The packaging A5 has the inner edges 45 a curved only at a centralportion while the portions closer to the ends are straight lines. Thepackaging A5 having such a structure was still effective to reduce theoccurrences of turned back edges, as demonstrated by the occurrence rateof 31%. This shows that the inner edge 45 a not curved at the ends isstill effective to distribute the stress, which would otherwise beconcentrated at the respective ends of the inner edge 45 a (at theintersections with the inner edges 43 a and 44 a).

Referring now to the comparative examples C1 to C4, the occurrence ratesrange from 51% to 73%, which are at most comparable to the occurrencerates obtained on the conventional packaging X. These results show thatthe occurrences of turned back edges at the oblique seal 45 cannot bereduced or may even be increased as long as the inner edges 45 a arecomposed only of straight lines, regardless of the shapes and locationsof the inner edges 45 a. As set forth above, the packaging according tothe present invention has an inner edge 45 a that is at least partlycurved as exemplified by the packagings A1 to A5 and achieves the effectof preventing the oblique seals 45 from turning back.

The pouch container packaging according to the present invention is notlimited to the embodiments described above. Various design changes canbe made to the specific structure of the packaging for a pouch containeraccording to the present invention.

REFERENCE SIGNS LIST

-   A1 to A5 packaging-   B1 pouch container-   1 outer film-   2 gusset film-   21 fold line-   22 cutaway portion-   3 spout-   31 cap-   41 top-edge central seal-   42 top-edge side seal-   43 side seal-   43 a inner edge-   44 bottom seal-   44 a inner edge-   45 oblique seal-   45 a inner edge-   46 sealing shoulder

1-6. (canceled)
 7. A packaging for a pouch container, the packaging comprising: a filling-and-pouring member disposed at a top of the packaging; a pair of outer films disposed on a front side and a back side, the outer films each having side edges, a bottom edge and oblique edges lying between the side edges and the bottom edge; and a pair of gusset films each disposed in a folded state between the outer films and having side edges and oblique edges, wherein the side edges of the outer films and the side edges of the gusset films are joined to provide side seals, the bottom edges of the respective outer films are joined to provide a bottom seal, and the oblique edges of the outer films and the oblique edges of the gusset films are joined to provide oblique seals, and the oblique seals each have an inner edge at least a part of which is curved, and each oblique seal has a narrow-width portion that is narrower in width than ends of the oblique seal.
 8. The packaging according to claim 7, wherein the inner edge of each oblique seal has a curved portion continuous with an inner edge of a side seal.
 9. The packaging according to claim 7, wherein the inner edge of each oblique seal has a curved portion continuous with an inner edge of the bottom seal.
 10. The packaging according to claim 7, wherein an entirety of the inner edge of each oblique seal is curved.
 11. A pouch container comprising: the packaging according to claim 7; and a substance contained in the packaging.
 12. The packaging according to claim 9, wherein the inner edge of the bottom seal has a curved portion that is seamlessly continuous with the curved portion of the inner edge of a corresponding one of the oblique seals. 